52 Pa. Code § 53.22
All tariffs shall contain a list of modifications of existing rules, regulations and rates, in the order specified in § 53.21 (relating to title page) and stating the page and rule or rate schedule effected, together with a brief statement of the modification. When a separate notice is filed as provided in § 53.21, the list of modifications, suitably identified by tariff and page number, shall be made a part of the notice instead of a part of the individual tariff or supplement. All modifications shall be identified throughout the tariff by the use of the following symbols following the particular rule or rate, or portion of the rule or rate, affected:
| Rule or rate | Symbol |
| Increase | (I) |
| Decrease | (D) |
| Change | (C) |
52 Pa. Code § 53.22
This section cited in 52 Pa. Code § 53.21 (relating to title page); and 52 Pa. Code §63.107 (relating to applications for authority).